obey the following graded commutation relations [1]}, [2]}
\(\lbrace {\cal D}_\alpha ,{\cal D}_\beta \rbrace &=&2{\rm i}{\cal D}_{\alpha \beta }-4{\rm i}{\cal S}M_{\alpha \beta }~,~~~~~~~~~\\\left[ {\cal D}_{\alpha \beta } , {\cal D}_\gamma \right] &=&- 2 \varepsilon _{\gamma (\alpha } {\cal S}{\cal D}_{\beta )} + 2 \varepsilon _{\gamma (\alpha } {\cal C}_{\beta ) \delta \rho } M^{\delta \rho }\nonumber \\&&+ \frac{2}{3} \big ( {\cal D}_\gamma {\cal S}M_{\alpha \beta }- 4 {\cal D}_{(\alpha } {\cal S}M_{\beta ) \gamma } \big )~,~~~~~~~~~\) 
